Hi,
There can be multiple reasons for this,
Can you see PAPI traffic between AP and the controller ? you can see by using the following command,
"show datapath session" there should be some traffic with UDP 8211.
can you see any output when you use "show ap database" , if you can see your AP , what are the flags showing,
Ex : L -- Unlicensed, E = Regulatory Domain Mismatch, I- Inactive
Some times status will be " Denied" due to CP sec.
Please provide me the status and flags so that I can help you fix the issue.
Please feel free for comeback for any further help on this.